Vane driving device

ABSTRACT

A vane driving device includes: a board having an opening; a blade changing an area of the opening, having a cam slot, and being elastically deformable; and a drive member transmitting a drive force from a drive source to the blade, and having a drive pin engaging the cam slot. The drive member is stopped by contacting the drive pin with at least one of end portions of the cam slot, when the blade is located in a fully opened state or in a small aperture state.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority toInternational Patent Application No. PCT/JP2008/069097 filed on Oct. 22,2008, which claims priority to Japanese Patent Application No.2007-311298 filed on Nov. 30, 2007, subject matter of these patentdocuments is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to vane driving devices.

2. Description of the Related Art

Conventionally, a vane driving device, such as an aperture deviceemployed in a camera or the like, includes: a board having an opening: ablade changing an area of the opening; a drive member transmitting adrive force from a drive source to the blade. The drive force istransmitted to the blade, thereto operate the blade. Specifically, thedrive force from the drive source is transmitted to the drive member viaa gear, so that this drive member drives the blade. Further, the bladeswings about a given position to change an area of the opening. Forexample, Japanese Unexamined Patent Application Publication No.2007-171238 discloses an aperture device in which an aperture ring isemployed as the drive member.

In such a vane driving device, the swinging range of the blade isrestricted by restricting the driving range of the drive member. Thedriving range of the drive member is restricted by contacting the drivemember with a stopper which has a projection shape and which is formedon the board. However, the drive force from the drive source istransmitted to such a drive member via the gear or the like, so that thetorque of the drive member is greater. Thus, the noise generated bycontact of the drive member and the stopper is larger.

SUMMARY OF THE INVENTION

It is therefore an object to provide a vane driving device having anoperation noise that is reduced.

According to an aspect of the present invention, there is provided avane driving device including: a board having an opening; a bladechanging an area of the opening, having a cam slot, and beingelastically deformable; and a drive member transmitting a drive forcefrom a drive source to the blade, and having a drive pin engaging thecam slot, wherein the drive member is stopped by contacting the drivepin with at least one of end portions of the cam slot when the blade islocated in a fully opened state or in a small aperture state.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described indetail with reference to the following drawings, wherein:

FIG. 1 is an exploded perspective view of the vane driving deviceaccording to the embodiment;

FIG. 2 is a front view of the vane driving device in which anelectromagnetic actuator is assembled into a shutter plate;

FIG. 3 is a front view of the vane driving device in which a drive ringis further assembled into the shutter plate;

FIG. 4 is a front view of the vane driving device, in a fully openedstate, in which an elastic gear, blades are further assembled into theshutter plate;

FIG. 5 is a front view of the vane driving device, in a small aperturestate, in which the elastic gear, the blades are further assembled intothe shutter plate;

FIG. 6 is a rear view of the vane driving device;

FIG. 7 is a view of a part of the vane driving device in the fullyopened state;

FIGS. 8A to 8C are explanatory views of the meshing of teeth portionsand a rotor pinion;

FIG. 9 is an explanatory view of the contact of the blade with the rotorpinion;

FIGS. 10A and 10B are enlarged views of the periphery of a drive pinpositioned at an end portion of a cam slot;

FIGS. 11A and 11B are cross-sectional views of the periphery of theelectromagnetic actuator;

FIG. 12 is an enlarged view of the periphery of an actuator chamberillustrated in FIG. 1;

FIGS. 13A and 13B are views partially illustrating the vane drivingdevice according to a first variation;

FIG. 14 is an enlarged view of the periphery of a rotor pinionillustrated in FIG. 13A; and

FIGS. 15A and 15B are views partially illustrating a vane driving deviceaccording to a second variation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description will be given of an embodiment according tothe present invention with reference to the drawings. FIG. 1 is anexploded perspective view of the vane driving device according to theembodiment. The vane driving device according to the embodimentincludes: a blade support plate 10; blades 20 a to 20 c; an elastic gear30 serving as a first gear; a drive ring 40 serving as a second gear; anelectromagnetic actuator 50; a shutter plate 60; and a flexible printedcircuit board 70, which are arranged in this order from the object sideto the image side, when the object side is located to the upper side inFIG. 1 and the image side is located to the lower side in FIG. 1.

The blades 20 a to 20 c, the elastic gear 30, the drive ring 40, and theelectromagnetic actuator 50 are housed between the blade support plate10 and the shutter plate 60. The blade support plate 10 and the shutterplate 60 have openings 11 and 61, defining the optical path, at theircenter portions, respectively. The electromagnetic actuator 50 transmitsits drive force to the blades 20 a to 20 c via the drive ring 40 and theelastic gear 30. The drive ring 40 has a ring shape. The drive ring 40is partially provided with a teeth portion 43, serving as a second teethportion to which the drive force is transmitted from the electromagneticactuator 50, at its outer periphery. The drive ring 40 is slidablysupported relative to the shutter plate 60. Specifically, a sliding edge45 slidably contacts an inner edge portion 65.

Further, the drive ring 40 has plural drive pins 44 a to 44 c along thesliding edge 45 at even intervals. The drive pins 44 a to 44 crespectively engage engagement holes 34 a to 34 c formed in the elasticgear 30. The elastic gear 30 is fixed on the drive ring 40 to overlap itin the rotational axis direction, that is, in the optical axisdirection. Furthermore, the elastic gear 30 is provided with a teethportion 33, serving as a first teeth portion, at its outer periphery soas to overlap the teeth portion 43 in the optical axis direction. Also,a circular arc slot 32, which serves as a deformation facilitatingportion and has a hole shape, is provided between the teeth portion 33and the rotational center of the teeth portion 33.

Specifically, the circular arc slot 32, which serves as a deformationfacilitating portion and has a hole shape, extends along the teethportion 33. The elastic gear 30 also has an opening 31 defining theoptical path at its center portion. The elastic gear 30 is thinner thanthe drive ring 40. Therefore, the elastic gear 30 is more deformablethan the drive ring 40. Moreover, the elastic gear 30 is made deformablein the radial direction by the circular arc slot 32. In addition, thediameter of the opening 31 is smaller than those of the openings 11 and61.

The blades 20 a to 20 c are arranged at the object side relative to theelastic gear 30. The blades 20 a to 20 c are provided with shaft holes22 a to 22 c at their end portions, respectively. The shaft holes 22 ato 22 c respectively engage support shafts 62 a to 62 c formed on theshutter plate 60. This allows the blades 20 a to 20 c to be swingablysupported with respect to the shutter plate 60. Moreover, the blades 20a to 20 c are respectively provided with cam slots 24 a to 24 c. The camslots 24 a to 24 c respectively engage the drive pins 44 a to 44 c.Therefore, by rotating the drive ring 40, the drive pins 44 a to 44 care respectively moved within the cam slots 24 a to 24 c, and the blades20 a to 20 c are respectively swung about the shaft holes 22 a to 22 c.Accordingly, the opening areas of the openings 11, 31, and 61 areadjustable. Consequently, the drive ring 40 serves as a drive member fortransmitting the drive force from the electromagnetic actuator 50 to theblades 20 a to 20 c.

Further, the blade support plate 10 is provided with escape holes 14 ato 14 c, for reliving the drive pins 44 a to 44 c, in the vicinity ofthe opening 11. Furthermore, the blade support plate 10 is provided witha shaft hole 15 supporting a rotary shaft 54 of the electromagneticactuator 50, as will be described later in more detail. Engagement pawls191, which are formed at an edge portion of the blade support plate 10,engage engagement portions 691, which are formed at an outer edgeportion 66 of the shutter plate 60. Engagement holes 192, which areformed in the blade support plate 10, fit projective portions 692, whichare formed at the outer edge portion 66 of the shutter plate 60. In thismanner, the blade support plate 10 is attached to the shutter plate 60.

The flexible printed circuit board (hereinafter referred to as FPC) 70,serving as a printed substrate, has a flexibility, and is fixed to theshutter plate 60 at an outer side surface thereof defining an actuatorchamber AC housing the electromagnetic actuator 50. The FPC 70 iselectrically connected to the electromagnetic actuator 50 and ensuresthe supply of electric power for the electromagnetic actuator 50.

FIG. 2 is a front view of the vane driving device in which theelectromagnetic actuator 50 is assembled into the shutter plate 60.Referring to FIGS. 1 and 2, a blade chamber SC for housing the blades 20a to 20 c and the actuator chamber AC for housing the electromagneticactuator 50 are provided in the shutter plate 60. The actuator chamberAC projects to the image side in the optical axis direction relative tothe blade chamber SC, and has a recess shape. The electromagneticactuator 50 includes a rotor 51, a stator 52, coils 53 a and 53 b, and arotor pinion 55, as illustrated in FIG. 2. The rotor 51 is magnetized tohave different polarities in its circumferential direction. The rotaryshaft 54 supports the rotor 51 and the rotor pinion 55 for integralrotation.

Moreover, as will be described later in more detail, the rotor pinion 55is integrated with the rotary shaft 54 which is not indicated by thereference numeral in FIG. 2. Also, the rotary shaft 54, the rotor pinion55 and the rotor 51 are formed by insert molding. Thus, the rotary shaft54, the rotor pinion 55, and the rotor 51 are integrally formed. Thestator 52 has a letter U shape and two arm portions, around which thecoils 53 a and 53 b are respectively wound. The end portions of thecoils 53 a and 53 b are electrically connected to the FPC 70. The stator52 is excited by energization of the coils 53 a and 53 b, so that themagnetic force generated between the stator 52 and rotor 51 rotates therotor 51 by a given range.

Further, the actuator chamber AC is provided with five boss portions 63serving to align the electromagnetic actuator 50. Furthermore, fourescape holes 671, which escape the end portions of the coils 53 a and 53b outwardly from the actuator chamber AC, are provided in the vicinityof the actuator chamber AC. The two escape holes 671 are provided in thevicinity of the opening 61, and the remaining two escape holes 671 areprovided at the outer periphery side. The end portions of the coils 53 aand 53 b are escaped outwardly through the escape holes 671, and areconnected to solder land portions of the FPC 70 serving as a printedsubstrate, thereby attaining the electrical connection. Thesearrangements will be described later in more detail.

FIG. 3 is a front view of the vane driving device in which the drivering 40 is further assembled into the shutter plate 60. As illustratedin FIG. 3, the drive ring 40 serving as a driven member is assembled tomesh the teeth portion 43 with the rotor pinion 55.

FIG. 4 is a front view of the vane driving device, in a fully openedstate, in which the elastic gear 30, the blades 20 a to 20 c are furtherassembled into the shutter plate 60. FIG. 5 is a front view of the vanedriving device, in a small aperture state, in which the elastic gear 30,the blades 20 a to 20 c are further assembled into the shutter plate 60.Referring to FIG. 4, the vane driving device is brought into the fullyopened state by positioning the blades 20 a to 20 c in receded positionsreceded from the openings 31 and 61. Also, referring to FIG. 5, thesmall aperture state, in which the opening amounts of the openings 31and 61 are reduced, is defined by positioning the blades 20 a to 20 c tocover the openings 31 and 61.

When the rotor pinion 55 rotates clockwise from the state illustrated inFIG. 4, the drive ring 40 rotates counterclockwise, whereas the blades20 a to 20 c swing clockwise, thereby shifting the state to the stateillustrated in FIG. 5.

FIG. 6 is a rear view of the vane driving device. The FPC 70 is fixed tothe outer wall, defining the actuator chamber AC of the shutter plate60, at the image side by use of a double-faced tape or the like.

FIG. 7 is a view of a part of the vane driving device in the fullyopened state. FIG. 7 illustrates the elastic gear 30, the drive ring 40,the blade 20 a, the rotor 51, and the rotor pinion 55, in order tofacilitate the understanding of the embodiment. The elastic gear 30 isarranged at the object side relative to the drive ring 40. In the fullyopened state, the outer edge of the blade 20 a contacts the rotor pinion55. This will be described later in more detail. Additionally, theelastic gear 30 and the drive ring 40 are fixed to each other such thatthe teeth portions 33 and 43 are slightly misaligned. Further, theelastic gear 30 is made thinner than the drive ring 40. Specifically,the thickness of the elastic gear 30 is reduced to about one-sixth ofthat of the drive ring 40. Further, the elastic gear 30 is made of asynthetic resin such as polyethylene terephthalate or acrylate resin,and is formed into a film shape. For this reason, the elastic gear 30 ismade of a material which is more deformable that of than the drive ring40 which is made of a general material such as polyacetal resin or nylonresin. As exemplified the material of the elastic gear 30 above, thematerial of the elastic gear 30 is not limited to the above one, and maybe any one that is more deformable than the drive ring 40.

Next, a description will be given of meshing of the teeth portions 33and 43 and the rotor pinion 55. FIGS. 8A to 8C are explanatory views ofthe meshing of the teeth portions 33 and 43 and the rotor pinion 55.FIG. 8A illustrates the state after the teeth portions 33 and 43 meshthe rotor pinion 55. FIG. 8B illustrates the state before the teethportions 33 and 43 mesh the rotor pinion 55. FIG. 8C illustrates anenlarged part of FIG. 8B. Additionally, the rotor pinion 55 is alsoillustrated in FIGS. 8A to 8C, in order to facilitate the understandingof the embodiment.

Referring to FIG. 8A, the teeth portion 33 includes plural toothportions 33 a, 33 b . . . , and the teeth portion 43 also includesplural tooth portions 43 a, 43 b . . . . As illustrated in FIG. 8A, atooth tip 331 a of the tooth portion 33 a radially and outwardlyprojects from a tooth tip 431 a of the tooth portion 43 a. Further, onetooth surface 332 a of the tooth portion 33 a projects from one toothsurface 432 a of the tooth portion 43 a in the circumferentialdirection. Furthermore, the other tooth surface 333 a of the toothportion 33 a substantially overlaps the other tooth surface 433 a of thetooth portion 43 a. This configuration also applies the tooth portions33 b and 43 b adjacent to each other. In addition, the rotor pinion 55includes plural tooth portions 55 a . . . . One tooth surface 552 a ofthe tooth portion 55 a contacts the tooth surface 332 b, and the othertooth surface 553 a of the tooth portion 55 a contacts both of the toothsurfaces 333 a and 433 a.

Further, the elastic gear 30 is provided with the circular arc slot 32extending along the teeth portion 33 in the circumferential direction,as illustrated in FIG. 7. By providing the circular arc slot 32, theelastic gear 30 is elastically deformed, specifically, in the radialdirection with ease. Thus, the circular arc slot 32 serves as adeformation facilitating portion for facilitating the elasticdeformation of the elastic gear 30. Moreover, since the elastic gear 30and the drive ring 40 are fixed to and overlapped with each other in theaxial direction by fitting the drive pins 44 a to 44 c into theengagement holes 34 a to 34 c, respectively, the elastic gear 30 and thedrive ring 40 serve as a pair of gears. Furthermore, the rotor pinion 55serves as a mating gear meshing the pair of gears.

In this way, since the teeth portion 33 projects outwardly from theteeth portion 43, when the rotor pinion 55 meshes the teeth portions 33and 43, the teeth portion 33 initially meshes the rotor pinion 55 inpriority to the teeth portion 43. Moreover, since the teeth portion 33is readily deformed in the radial direction at the circumferential rangeby providing the circular arc slot 32 in the elastic gear 30, the teethportion 33 is allowed to mesh the rotor pinion 55, to be closer than tothe teeth portion 43. This suppresses the backlash between the rotorpinion 55, and the elastic gear 30 and the drive ring 40 serving as apair of gears. That is, the rotor pinion 55, and the elastic gear 30 andthe drive ring 40 are always suppressed from rattling such that the axisof the rotor pinion 55 is spaced apart from those of the elastic gear 30and the drive ring 40. This reduces the operation noise caused by theaxial backlash generated between the rotary shaft 54 and the shaft hole15 formed in the blade support plate 10, between the rotary shaft 54 anda shaft hole 64 formed in the shutter plate 60, or between the drivering 40 and the inner edge portion 65 provided in the shutter plate 60.

Additionally, the projection amount of the tooth surface 332 a from thetooth surface 432 a in the circumferential direction is different fromthat of the tooth surface 333 a from the tooth surface 433 a. That is,the tooth surface 552 a contacts the tooth surface 332 b, whereas thetooth surface 553 a contacts both of the tooth surfaces 333 a and 433 a.Unlike the elastic gear 30, the drive ring 40 does not employ aconfiguration for facilitating its elastic deformation. Thus, the amountof the elastic deformation of the elastic gear 30 is variable inresponse to the rotational direction of the rotor pinion 55. That is,when the rotor pinion 55 rotates counterclockwise, the tooth surface 332b serves as a transmitted surface to which the drive force istransmitted from the rotor pinion 55, whereas, when the rotor pinion 55rotates clockwise, the tooth surfaces 333 a and 433 a serve astransmitted surfaces to which the drive force is transmitted from therotor pinion 55. Accordingly, when the rotor pinion 55 rotatescounterclockwise, since the tooth surface 332 b is elastically deformedwith ease, the tooth surfaces 552 a and 332 b constantly contact eachother to transmit the drive force from the rotor pinion 55. This mainlysuppresses the backlash caused between the rotor pinion 55 and the drivering 40 in the normal line direction, and also reduces the operationnoise caused by the backlash. Further, when the rotor pinion 55 rotatesclockwise, the transmission accuracy of the rotational drive force ismainly improved by contacting the tooth surface 433 a with the toothsurface 553 a.

Further, when the rotor pinion 55 rotates clockwise, the blades 20 a to20 c swing in such a direction to reduce the opening areas of theopenings 11, 31, and 61. Thus, the drive force is transmitted from therotor pinion 55 to the tooth surfaces 433 a and 433 b, in the processfor reducing the opening areas. For this reason, the drive force istransmitted to the teeth portion 43 of the drive ring 40 which does notemploy the configuration for facilitating the elastic deformation.Consequently, the accuracy of the aperture can be maintained.

Next, a description will be given of the state of the teeth portions 33and 43 before meshing the rotor pinion 55. Referring to FIGS. 8B and 8C,the tooth surface 333 a slightly projects outwardly from the toothsurface 433 a in the circumferential direction. In the state before themesh, the projection amount of the tooth surface 332 a from the toothsurface 432 a in the circumferential direction is also different fromthat of the tooth surface 333 a from the tooth surface 433 a. Thisconfiguration also applies the tooth surfaces 333 b and 433 b. In thedesign of the distance between the axis of the rotor pinion 55, and theaxes of the elastic gear 30 and the drive ring 40, it is necessary toconsider the projection amount of the tooth surface 333 a from the toothsurface 433 a. That is, it is necessary to design the distance betweenthe axis of the rotor pinion 55, and the axes of the elastic gear 30 andthe drive ring 40, such that the projection amount of the tooth surface333 a from the tooth surface 433 a is made zero by a pressing force ofthe rotor pinion 55 pressed against the elastic gear 30, so that thetooth surfaces 433 a and 333 a are substantially overlapped with eachother. This suppresses the backlash and improves the transmissionaccuracy of the rotational drive force.

Next, a description will be given of the elastic gear 30 in more detail.As illustrated in FIGS. 1 and 7, the circular arc slot 32 is arrangedalong the teeth portion 33 partially provided at the outer edge of theelastic gear 30, is arranged between the teeth portion 33 and itsrotation center, and extends in the circumferential direction. With sucha configuration, the elastic deformation of the elastic gear 30 in aradial direction can be facilitated in its circumferential range.

Further, the elastic gear 30 and the drive ring 40 are fixed to eachother by respectively engaging the drive pins 44 a to 44 c with theengagement holes 34 a to 34 c. Therefore, the drive pins 44 a to 44 cand the engagement holes 34 a to 34 c serve as engagement means forfixing them by engaging. In this manner, the elastic gear 30 and thedrive ring 40 can be fixed to each other by a simple structure, therebyimproving the assembling workability.

Furthermore, the engagement holes 34 a to 34 c are arranged at theradially inner side from the circular arc slot 32. This reason is asfollows. When the means for fixing the elastic gear 30 and the drivering 40 is provided at the radially inner side from the circular arcslot 32, the elastic gear 30 is fixed to the drive ring 40 at theirportions located between the circular arc slot 32 and the rotor pinion55. In this case, since it is difficult to transmit the pressing forceof the rotor pinion 55 against the elastic gear 30 to the circular arcslot 32, the circular arc slot 32 does not absorb the pressing forceexerted from the rotor pinion 55, whereby the elastic deformation of theelastic gear 30 may be restricted in the radial direction.

Moreover, the drive pins 44 a to 44 c respectively engage the cam slots24 a to 24 c. These engagements permit the drive force of the drive ring40 to be transmitted to the blades 20 a to 20 c. In this manner, thedrive ring 40 is provided with the structure for transmitting the driveforce of the electromagnetic actuator 50 to the blades 20 a to 20 c.This is because when the elastic gear 30 is provided with the abovestructure, the drive force may not be transmitted with stability, sincethe elastic gear 30 is elastically deformable with ease.

Additionally, as mentioned above, the drive pins 44 a to 44 c have afunction for transmitting the drive force of the electromagneticactuator 50 to the blades 20 a to 20 c, and also have a function forfixing the elastic gear 30 to the drive ring 40. This reduces the numberof the parts, since the fixing function and the transmitting function donot have to be separately provided. Moreover, the number of the parts isreduced, so that the space within the vane driving device can beeffectively used, and the assembling workability is improved.

Further, as illustrated in FIGS. 1, 4, and 5, the rotor pinion 55, theteeth portions 43 and 33 serve as a gear mechanism for transmitting thedrive force of the electromagnetic actuator 50 to the blades 20 a to 20c. This gear mechanism is composed only of the rotor pinion 55integrated with the rotor 51, and the elastic gear 30 and the drive ring40 serving as a pair of gears. This reduces the number of the parts, ascompared to a structure which transmits the drive force via many gears.This reduces the number of the meshing points of the gears, and alsoreduces the operation noise for them.

Next, a description will be given of the contact of the blade 20 a withthe rotor pinion 55. FIG. 9 is an explanatory view of the contact of theblade 20 a with the rotor pinion 55. FIG. 9 is an enlarged view of theperiphery of the rotor pinion 55 illustrated in FIG. 7. Additionally,any other members are omitted in FIG. 9. Referring to FIG. 4, the blade20 a contacts the rotor pinion 55 with the opening area being in thefully opened state. This contact stops the rotation of the rotor pinion55. Thus, the blade 20 a serves as stop means for being into and contactwith the rotor pinion 55 and for stopping the rotation of the rotorpinion 55 by contacting the rotor pinion 55. Therefore, the rotations ofthe elastic gear 30 and the drive ring 40 are stopped, thereby causingthe blades 20 a to 20 c to be located at the receded positions.

Further, the rotor pinion 55 is arranged closer to the electromagneticactuator 50 than to the drive ring 40 in the transmitting pass on whichthe drive force is transmitted from the electromagnetic actuator 50 tothe blades 20 a to 20 c. Thus, by directly stopping the rotor pinion 55,the transmission of this drive force can be disconnected before thedrive force becomes greater in the process of transmitting the driveforce of the electromagnetic actuator 50 to the blades 20 a to 20 c.Accordingly, this reduces the impact noise caused by the contact, ascompared to a conventional case where the shutter plate 60 is providedwith a projection shape stopper and the drive ring 40 is stopped bycontacting this stopper.

Furthermore, although such stop means may be separately provided fromthe blade 20 a, the number of the parts can be reduced by employing theblade 20 a as the stop means.

Also, the blade 20 a contacts the rotor pinion 55 in the recededposition. This reduces the influence to be applied on the opening area,even when the blade 20 a is vibrated by the impact, caused by thecontact of the blade 20 a with the rotor pinion 55, or the like.

Moreover, as described above, since the rotor pinion 55, the rotaryshaft 54, and the rotor 51 are integrated by insert molding, theyintegrally rotate. That is, the rotor pinion 55 and the rotor 51integrally rotate. Thus, the rotor pinion 55 is a closest gear to theelectromagnetic actuator 50 serving as a drive source. For example, likethe conventional vane driving device, in a case where the drive force istransmitted via plural gears including an intermediate gear in order toreduce a rotational speed of the electromagnetic actuator 50, when theintermediate gear is contacted to be stopped, the following problem mayoccur. In such an intermediate gear, its rotational speed is reducedmore than that of a gear closer to the drive source, and its torque isincreased. This may increase the operation noise caused by the contactof the intermediate gear. However, as described in the presentembodiment, the rotor pinion 55, which is closest to the drive source,is contacted by the blade 20 a and is then stopped, thereby stopping therotation of the rotor pinion 55 with ease, and thereby also reducing theimpact noise at that time.

Further, as illustrated in FIG. 9, the blade 20 a is provided with acut-out portion 25 a at a position where the blade 20 a contacts therotor pinion 55. The cut-out portion 25 a is formed such that the outeredge of the blade 20 a has a circular arc to be comparatively small. Thecurvature radius of the cut-out portion 25 a corresponds to the maximumradius from the center of the rotor pinion 55 to the tooth tip. Asillustrated in FIG. 9, the length of the cut-out portion 25 a and therotational position of the rotor pinion 55 are designed such that thecut-out portion 25 a contacts the two tooth portions 55 a and 55 b ofthe rotor pinion 55 when the blade 20 a is positioned at the recededposition. Since the cut-out portion 25 a contacts the two tooth ends ofthe tooth portions 55 a and 55 b, the contact area of the blade 20 a andthe rotor pinion 55 can be increased, thereby assisting in stopping therotation of the rotor pinion 55. That is, the cut-out portion 25 aserves as an engagement structure for contacting the rotor pinion 55 toassist in stopping the rotation thereof.

Furthermore, the contact at two positions alleviates the impact. Inaddition, each of the blades 20 a to 20 c has a thin shape to facilitateits elastic deformation. This further alleviates the impact based on thecontact of the blade 20 a with the rotor pinion 55. Also, referring toFIGS. 7 and 9, the cam slot 24 a is arranged close to the cut-outportion 25 a. This cam slot 24 a facilitates the elastic deformation ofthe blade 20 a in its drive direction. This cam slot 24 a is arranged inthe vicinity of the contact position so as to absorb the impact causedby the contact. Further, since the cam slot 24 a extends along the arcedge of the blade 20 a having a fan shape, the cam slot 24 a can beenlarged relative to the blade 20 a, and the elastic deformation of theblade 20 a can be facilitated in its drive direction.

Next, a description will be given of the engagement of the cam slot 24 aand the drive pin 44 a.

FIGS. 10A and 10B are enlarged views of the periphery of the drive pin44 a positioned at an end portion of the cam slot 24 a. FIG. 10Aillustrates the periphery of the drive pin 44 a in the fully openedstate. FIG. 10B illustrates the periphery of the drive pin 44 a in thesmall aperture state where the opening area is minimum. The drive pin 44a does not contact one end portion 241 a of the cam slot 24 a in thefully opened state, as illustrated in FIG. 10A. In contrast, the drivepin 44 a contacts the other end portion 242 a of the cam slot 24 a inthe small aperture state, as illustrated in FIG. 10B. These arrangementsapply the drive pins 44 b and 44 c and the cam slots 24 b and 24 c.

Therefore, in the small aperture state, the drive pins 44 a to 44 ccontact end portions of the cam slots 24 a to 24 c, respectively,thereby stopping the drive ring 40 and positioning the blades 20 a to 20c in such positions to cover the opening. As mentioned above, each ofthe blades 20 a to 20 c has a thin shape to facilitate its elasticdeformation. Accordingly, this reduces the impact noise, as compared toa conventional case where the shutter plate 60 is provided with astopper and the drive ring 40 contacts the stopper to stop.Additionally, the shutter plate 60 does not have to be provided with thestopper, thereby simplifying the structure. Moreover, the drive pins 44a to 44 c simultaneously contact end portions of the cam slots 24 a to24 c, respectively, thereby distributing the impact applied to eachmember.

Further, in the fully opened state, the blade 20 a contacts the rotorpinion 55 to stop the drive of the drive ring 40, as mentioned above.For example, when the blade 20 a contacts the rotor pinion 55 to be bentin the optical direction and runs onto a part of the rotor pinion 55,the drive pin 44 a contacts the one end portion 241 a to stop the driveof the drive ring 40.

In addition, although the drive pin 44 a does not contact the one endportion 241 a in the fully opened state, as illustrated in FIG. 10A, thedrive pin 44 a may contact the one end portion 241 a. In this case, thedrive pin 44 a and the blade 20 a simultaneously contacts the one endportion 241 a and the rotor pinion 55, respectively, thereby furtherdistributing the impact applied to each member and reducing theoperation noise.

Next, a description will be given of the electromagnetic actuator 50.FIGS. 11A and 11B are cross-sectional views of the periphery of theelectromagnetic actuator 50. FIG. 11A is a cross sectional view takenalong line A-A in FIG. 6. FIG. 11B is a partially enlarged view of FIG.11A. Referring to FIG. 11A, the actuator chamber AC, which is defined attwo boards between the shutter plate 60 and the blade support plate 10,is formed as a drive source chamber and houses the rotor 51, the stator52, the rotary shaft 54 and the like. Further, the rotary shaft 54 hasone end portion 541 which is located at the image side and which issupported for sliding with respect to the shaft hole 64. The rotaryshaft 54 has the other end portion 542 which is located at the objectside and which is supported for sliding by the shaft hole 15 formed inthe blade support plate 10. Therefore, the rotary shaft 54 is rotatablysupported between the blade support plate 10 and the shutter plate 60.Accordingly, the shutter plate 60 serves as a chassis for housing theelectromagnetic actuator 50 and supporting the rotary shaft 54 forrotation.

As illustrated in FIG. 11B, the shaft hole 64 is filled with a lubricantL for lubricating the one end portion 541 and the shaft hole 64. Here,the diameter of the shaft hole 64 is made smaller toward the outsidefrom the inside of the shutter plate 60. That is, the shaft hole 64 hasa diameter slightly larger than that of the one end portion 541, and isconically shaped such that the diameter is smaller as apart from the oneend portion 541. The shaft hole 64 passes through the actuator chamberAC. The FPC 70 is fixed at the outside of the shaft hole 64. Thelubricant L is filled in a space defined by the one end portion 541, theshaft hole 64, and the FPC 70. An example of the lubricant L is agrease. In this manner, by filling the lubricant L, the operation noisein accordance with the rotation of the rotary shaft 54 can be reduced bymeans of a simple structure. Further, such a simple structure alsosuppresses the manufacturing cost.

Next, a description will be given of the assembling order in which therotary shaft 54 is assembled into the shaft hole 64. First, the FPC 70is fixed to the outer wall surface of the shutter plate 60, that is, toan image-side surface opposite to the actuator chamber AC by adouble-faced tape. At this time, the shutter plate 60 is fixed to sealthe shaft hole 64. Next, the lubricant L is filled in the shaft hole 64from the actuator chamber AC side to the single shutter plate 60. Theshaft hole 64 has a diameter becoming smaller to the outside from theinside of the actuator chamber AC, and is sealed with the FPC 70, asmentioned above. For this reason, when the lubricant with certain highviscosity is filled, the lubricant L may not be leaked out from theshaft hole 64.

Next, the stator 52, around which the coils 53 a and 53 b are wound, ispress fitted into the actuator chamber AC with engaging the bossportions 63. Next, the one end portion 541, which is not provided withthe rotor pinion 55, of a part in which the rotor pinion 55, the rotaryshaft 54, and the rotor 51 are integrated, is inserted into the shafthole 64. In this situation, the lubricant L within the shaft hole 64 ispressed outwardly from the actuator chamber AC, whereas the shaft hole64 is shaped such that its diameter becomes smaller than that of the oneend portion 541, as illustrated in FIG. 11B. Moreover, the shaft hole 64is sealed with the FPC 70. For this reason, the one end portion 541 ismerely inserted into a partway of the shaft hole 64, thereby suppressingthe lubricant L from being leaked out from the shaft hole 64 by thepressure of the one end portion 541. Further, since the shaft hole 64passes through the shutter plate 60, even after the one end portion 541is inserted into the shaft hole 64, air mixed into the lubricant L canbe leaked outwardly.

As mentioned above, the FPC 70 is fixed on the shutter plate 60 to sealthe shaft hole 64 from its outside. This prevents the lubricant L frombeing leaked from the shaft hole 64 while the vane driving deviceoperating. Further, the FPC 70 eliminates the necessity of separatelyproviding a member for preventing the leak of the lubricant L, therebyreducing the number of the parts. In this manner, the rotary shaft 54 isassembled into the shaft hole 64.

In addition, since the shaft hole 64 is shaped such that its diameter ismade smaller than that of the one end portion 541, the filled space, inwhich the lubricant L is filled, is prevented from being pressed by therattling of the rotary shaft 54 in the axial direction, after theassembling of the vane driving device is accomplished. Further, the oneend portion 541 of the rotary shaft 54 is located apart from the blades20 a to 20 c, and the other end portion 542 is close to the blades 20 ato 20 c. Since the shaft hole 64 supports the one end portion 541 apartfrom the blades 20 a to 20 c, the lubricant L is suppressed from beingleaked from the shaft hole 64 into the actuator chamber AC and beingattached to the blades 20 a to 20 c, after the assembling isaccomplished. Furthermore, the structure of the vane driving device issimpler in the far side from the blades 20 a to 20 c than near sidethereto, thereby facilitating the work of filling the lubricant L, evenin the assembling stage.

Next, a description will be given of a structure of the actuator chamberAC. FIG. 12 is an enlarged view of the periphery of the actuator chamberAC illustrated in FIG. 1. Referring to FIG. 12, the actuator chamber ACand the blade chamber SC are continuous with each other. That is, theactuator chamber AC and the blade chamber SC are provided between theblade support plate 10 and the shutter plate 60. In the conventionalvane driving device, when the actuator serving as a drive source isformed into a single unit, its thickness in the optical axis directionis increased by the thickness of the shutter plate 60 and that of acover of the unitized actuator. However, the configuration according tothe present embodiment is capable of reducing the thickness in theoptical axis direction. Further, as illustrated in FIGS. 11A and 11B,the rotor 51, the rotary shaft 54, and the rotor pinion 55 areintegrated into a single unit, and their size is made minimum in thedirection of the rotary shaft without the gap between the parts.Therefore, the parts are effectively arranged in the direction of therotary shaft, thereby suppressing the increase in the thickness in theoptical axis direction, and thereby reducing the number of the parts,and suppressing the manufacturing cost. In addition, the actuatorchamber AC is provided with reliving holes 68 for relieving thethickness of the coils 53 a and 53 b in the optical axis direction.

Next, a description will be given of the structure for facilitating thewiring work of the coils 53 a and 53 b of the electromagnetic actuator50. The FPC 70 is arranged on the outer surface opposite to the actuatorchamber AC. Therefore, the lengths of the coils 53 a and 53 b extendingto the FPC 70 can be shortened, so the coils 53 a and 53 b can beconnected to the FPC 70 with ease. This facilitates the wiring work ofthe coils 53 a and 53 b. This also reduces the manufacturing cost.

Further, four escape holes 671 are provided in the vicinity of theactuator chamber AC of the shutter plate 60, as illustrated in FIG. 12.Each of the escape holes 671 has a slit shape. A guide groove 672extends in the optical axis direction to be continuous with the escapehole 671. Here, the escape hole 671 and the guide groove 672 serve asopenings for escaping the wires of the coils 53 a and 53 b outwardlyfrom the actuator chamber AC serving as a drive source chamber. Theguide groove 672 extends to the surface, of the shutter plate 60, onwhich the FPC 70 is fixed. The four guide grooves 672 correspond to thefour escape holes 671. The work for wiring the coil is performed asfollow. For example, after the FPC 70 is fixed to the outer wallsurface, that is, to the image-side surface opposite to the actuatorchamber AC, the electromagnetic actuator 50 is assembled into theactuator chamber AC. Next, one end of the coil 53 a extends outwardlyfrom the escape hole 671 located near the one end, respectively. Then,the wire of the coil 53 a extends outwardly to the FPC 70 along theguide groove 672, and is connected to the solder land portion thereof.The above mentioned work also applies to the other end of the coils 53 aand 53 b. In this way, the escape holes 671 serves as escaping the wiresof the coils 53 a and 53 b outwardly from the actuator chamber AC, andthe guide grooves 672 serves as guiding the wires of the coils 53 a and53 b to the FPC 70. These arrangements facilitate the work for wiringthe coils 53 a and 53 b.

Next, a description will be given of a variation of the vane drivingdevice. FIGS. 13A and 13B are views partially illustrating the vanedriving device according to a first variation. Additionally, like thevane driving device mentioned above, the vane driving device accordingto the variation has three blades. The same components have the samereference numerals in order to avoid a duplicated description. FIG. 13Ais a view partially illustrating the vane driving device according tothe first variation. FIG. 13A illustrates, a drive ring 40A, a blade 20aA, a rotor pinion 55A, and a gear train 80A. FIG. 13A illustrates astate in which the blade 20 aA is positioned at a receded position froman opening.

The rotor pinion 55A is press fitted onto a rotary shaft, notillustrated. By rotating the rotor pinion 55A, its drive force istransmitted to the gear train 80A, thereby meshing the gear train 80Awith a teeth portion 43A partially formed in the outer periphery of thedrive ring 40A. Therefore, the teeth portion 43A rotates to swing theblade 20 aA about a shaft hole 22 aA. FIG. 13B is an enlargedperspective view of the rotor pinion 55A. Referring to FIG. 13B, therotor pinion 55A includes: a lower teeth portion 551A composed of pluraltooth portions; and an upper teeth portion 552A composed of two toothportions and overlapping the lower teeth portion 551A to shape twostages. The rotor pinion 55A is made of a synthetic resin. The lowerteeth portion 551A and the upper teeth portion 552A are integrated. Thedrive force is transmitted to the gear train 80A via the lower teethportion 551A.

FIG. 14 is an enlarged view of the periphery of the rotor pinion 55Aillustrated in FIG. 13A. Referring to FIG. 14, a cut-out portion 25 aAis provided in the outer periphery of the blade 20 aA. When the blade 20aA is positioned at the receded position, the cut-out portion 25 aAcontacts the upper teeth portion 552A. Further, the lower teeth portion551A is positioned at the rear side of the blade 20 aA. The upper teethportion 552A is formed to serve as a projection portion projectingoutwardly and radially. Thus, when the upper teeth portion 552A contactsthe cut-out portion 25 aA, the upper teeth portion 552A engages thecut-out portion 25 aA, thereby stopping the rotation of the rotor pinion55A. That is, the upper teeth portion 552A serves as an engagementstructure to aid in stopping the rotation of the rotor pinion 55A withthe blade 20 aA contacted with the rotor pinion 55A. With such aconfiguration, the rotation of the rotor pinion 55A is also stopped by asimple structure.

FIGS. 15A and 15B are views partially illustrating a vane driving deviceaccording to a second variation. FIG. 15A is a front view of the vanedriving device in a fully opened state according to the secondvariation. FIG. 15B is a front view of the vane driving device in afully closed view according to the second variation. Referring to FIGS.15A and 15B, the vane driving device according to the second variationincludes a blade 20 d in addition to the blades 20 a to 20 c. The blade20 d is swingably supported by the support shaft 62 a, like the blade 20a. The blade 20 d is arranged at the object side with respect to theblade 20 a. Further, the blade 20 d is provided with a cam slot 24 dhaving a circular arc shape. The cam slot 24 d engages the drive pin 44a. In the state illustrated in FIG. 15A, that is, in the state where theopening is fully opened, the blade 20 d contacts the rotor pinion 55 tostop the rotation thereof. Thus, the blade 20 d serves as stop means forcontacting the rotor pinion 55 and for stopping the rotation of therotor pinion 55.

While the preferred embodiments of the present invention have beenillustrated in detail, the present invention is not limited to theabove-mentioned embodiments, and other embodiments, variations andmodifications may be made without departing from the scope of thepresent invention.

In the above embodiments, the blade support plate 10 is arranged at theobject side. However, the vane driving device may be configured suchthat the shutter plate 60 is arranged at the object side and the bladesupport plate 10 is arranged at the image side.

An intermediate gear may be provided between the rotor pinion 55 and theteeth portions 33 and 43 to contact the blade 20 a and stop the drive ofthe drive ring 40.

Although the elastic gear 30 and the drive ring 40 serve as a pair ofgears, the present invention is not limited to these arrangements. Forexample, an intermediate gear may be employed as such a pair of gears.

In a case where an intermediate gear is employed as a pair of gearsmentioned above, the other tooth surface, of the second tooth portion ofthe second gear not provided with a deformation facilitating portion,may transmit the drive force to a mating gear meshing the intermediategear.

In the above embodiment, the elastic gear 30 is formed of a syntheticresin. However, a sheet member made of polyethylene terephthalate oracrylate resin, a generally antireflective film, a light shielding filmsuch as a somablack film (SOMAR corporation) may be formed by pressing.

In the above embodiment, each of the blades 20 a to 20 c is made thin tobe elastically deformable with ease. However, a manufacturing method ofthe blades is not limited to, and the blades may be formed by eithermolding or pressing.

In the above embodiment, the rotor pinion 55, the rotary shaft 54, therotor 51 are integrated by inserting. However, all the rotor pinion 55and the rotary shaft 54 may be integrated.

In the embodiment, a printed substrate employs the flexible printedcircuit board 70. However, the printed substrate may employ a rigidsubstrate made of a material with rigidity, such as an epoxy resin Inthe embodiment, although the escape holes 671 and the guide grooves 672are formed in the shutter plate 60, these configurations may be formedin the blade support plate 10.

Finally, several aspects of the present invention are summarized asfollows.

According to an aspect of the present invention, there is provided avane driving device including: a board having an opening; a bladechanging an area of the opening, having a cam slot, and beingelastically deformable; and a drive member transmitting a drive forcefrom a drive source to the blade, and having a drive pin engaging thecam slot, wherein the drive member is stopped by contacting the drivepin with at least one of end portions of the cam slot when the blade islocated in a fully opened state or in a small aperture state.

Such a configuration reduces the operation noise, as compared to aconventional vane driving device in which the drive member contacts astopper formed on the board to be stopped. Further, it is unnecessary toprovide the stopper on the board, thereby simplifying the structure.

In the above configuration, the blade may include plural blades; and thedrive pin may include plural drive pins engaging cam slots of the pluralblades, respectively.

This arrangement distributes the impact applied to each member.

In the above configuration, the vane driving device may include stopmeans movable into and out of contact with a gear transmitting the driveforce from the drive source to the drive member, and stopping therotation of the gear by contacting the gear, wherein the stop means maybe in contact with the gear at the same time when the drive pinscontacts the end portion of the cam slot, when the blade is located inthe fully opened state or in the small aperture state. This arrangementfurther distributes the impact applied to each member.

In the above configuration, the stop means may be the blade; and the camslot may be provided near the contact point to absorb the impactgenerated by contact of the blade and the gear. With such aconfiguration, the operation noise can be reduced.

In the above configuration, the blade may have a thin shape to beelastically deformable.

With such a configuration, the cam slot further absorbs the impact bycontact of the blade and the gear, thereby reducing the operation noise.

1. A vane driving device comprising: a board having an opening; a blade changing an area of the opening, having a cam slot, and being elastically deformable; and a drive member transmitting a drive force from a drive source to the blade, and having a drive pin engaging the cam slot, wherein the drive member is stopped by contacting the drive pin with at least one of end portions of the cam slot when the blade is located in a fully opened state or in a small aperture state.
 2. The vane driving device of claim 1, wherein: the blade includes plural blades; and the drive pin includes plural drive pins engaging cam slots of the plural blades, respectively.
 3. The vane driving device of claim 2, further comprising stop means movable into and out of contact with a gear transmitting the drive force from the drive source to the drive member, and stopping the rotation of the gear by contacting the gear, wherein the stop means is in contact with the gear at the same time when the drive pins contacts the end portion of the cam slot, when the blade is located in the fully opened state or in the small aperture state.
 4. The vane driving device of claim 3, wherein: the stop means is the blade; and the cam slot is provided near the contact point to absorb the impact generated by contact of the blade and the gear.
 5. The vane driving device of claim 1, wherein the blade has a thin shape to be elastically deformable. 